Weatherstrip tape and method for producing the same

ABSTRACT

The present invention relates to an adhesive tape and to a method for its manufacture, the tape comprising: (A) a heat-activatable adhesive resin layer, wherein the resin is a polymer of one or more monomers selected from the group consisting of olefins, and (B) a pressure-sensitive adhesive layer, comprising an acrylic-type pressure sensitive adhesive, wherein said pressure sensitive adhesive layer is permanently and directly bonded to a first major surface of said heat-activatable adhesive layer. The present invention also relates to an intermediate article comprising the heat-activatable adhesive resin layer (A) releasably bonded to a support layer, to a composite article comprising the adhesive tape and a rubber article bonded to the second major surface of the heat-activatable layer (A), and to a vehicle comprising the composite article.

FIELD OF THE INVENTION

The present invention relates to a dual-functional adhesive tape (oftenreferred to as weatherstrip tape), more specifically to an adhesive tapecomprising a layer of heat-activatable polyolefin adhesive and a layerof acrylic-type pressure-sensitive adhesive, wherein saidpressure-sensitive adhesive layer is permanently and directly bonded toa first major surface of said heat-activatable adhesive layer.

BACKGROUND OF THE INVENTION

Pressure-sensitive adhesives are extremely popular for use in attachmenttapes. Their use allows for fast, easy attachment of product componentswithout the use of tools, messy liquid adhesives, or mechanicalfasteners. Pressure-sensitive adhesives are available with a widevariety of properties depending on the particular application, e.g. typeof substrate. Acrylic-type pressure sensitive adhesives are readilyavailable and provide a good balance of tack, shear and peel propertieson a variety of substrates and at relatively low costs.

Domestic and automotive weatherstrip seals and gaskets are commonlymanufactured from materials such as ethylene-propylene-diene monomer andneoprene. These compositions are characterized as low surface energyelastomers.

For many years there has existed a desire for pressure-sensitiveadhesive coated polyolefin products in which the pressure-sensitiveadhesive is firmly bonded to the polyolefin and remains so at elevatedtemperatures. Although it is comparatively easy to bond rubber-typepressure-sensitive adhesives to polyolefin substrates, the adhesive bondtends to weaken and the product to be subject to failure at temperaturesat about 65° C. or higher. Although acrylic-type pressure-sensitiveadhesives have superior heat-resistance, they do not normally bondeffectively to polyolefin substrates. In fact, polyolefin films arefrequently used as release liners for acrylic adhesives.

Various types of treatments have been attempted, in order to increasethe adhesion between a polyolefin substrate and a pressure-sensitiveadhesive. However, durability of the surface treatment has oftentimesbeen a problem. Use of a layer or coating of material which is a goodsubstrate for the adhesive has also been attempted. However, the weaklink in this system is the interface between the polyolefin and thecoating.

For example, heat-activatable polyolefin adhesives, e.g., polyethylene,polypropylene, or polyallomer (an ethylene-propylene copolymer) are wellknown for use on polyolefin substrates. However, such adhesives do notprovide the processing and application convenience of pressure-sensitiveadhesives. Furthermore, such adhesives do not yield high performance onall low-energy surfaces. In particular, heat-activatable polyolefinadhesives do not provide a sufficiently permanent bond to acrylic-typepressure sensitive adhesives.

EP-B-0 679 123 relates to a composite profile having a sealing profileand an adhesive tape, wherein the adhesive tape has a flexiblesupporting layer, wherein an adhesive layer covered with a removableliner is applied to a first surface of the supporting layer, wherein thesupporting layer is made of foam, and wherein a second surface of thesupporting layer opposite the first surface is bonded with a countersurface of the sealing profile to form a composite profile,characterized in that at least the second surface of the supportinglayer is melted via the application of heat at 100° C. to 400° C. andwelded with the preheated counter surface of the sealing profile.

EP-A-0 384 598 describes a dual-functional adhesive tape including alayer of a heat-activatable adhesive and a layer of pressure-sensitiveadhesive which is made by adhering the pressure-sensitive adhesive to aionizing-radiation grafted primer layer coated onto the heat-activatableadhesive.

U.S. Pat. No. 4,563,388 discloses an adhesive product comprising apolyolefin substrate and an acrylic-type pressure-sensitive adhesivewhich is bonded by means of a graft polymerized vinyl-coating applied onthe polyolefin substrate.

Previously known dual-functional adhesive tapes incorporatingheat-activatable polyolefin layer and an intermediate layer have beenfound to be prone to stiffness caused by the selection of the polyolefinlayer. Stiffness of the polyolefin heat-activated layer can contributeto stiffness of the overall weatherstrip construction and makes itdifficult for end-users to handle. Excessive stiffness also makes thetape less conformable and thus difficult to apply to irregularly curvedsurfaces, particularly those encountered in automotive door sealingoperations.

Moreover, the application of an additional intermediate layer is verylabor and cost intensive. The use of such intermediate layers also doesnot yield an entirely satisfactory bond over a wide variety ofconditions. Fasteners of the type described in the aforementionedpatents are particularly useful in the automotive industry. Automobileinteriors, however, are often subject to extreme temperature andhumidity conditions, for instance when a closed automobile remains inthe sun for extended periods of time and/or when humidity has beenallowed to enter the inside of the car.

SUMMARY OF THE INVENTION

It has now been found that the bond between the polyolefin and thepressure-sensitive adhesive is weakened in the presence of humidity evenwhen a priming or graft intermediate layer is used, thereby causingdelamination and disintegration of the tape.

There is further known a dual-functional adhesive tape having aheat-activatable resin directly bonded to an acrylic adhesive layerwherein the heat-activatable resin layer is a layer of a copolymer ofethylene and acrylic acid. A disadvantage of this type ofdual-functional adhesive tape is its low heat resistance.

It is a desire of the present invention to overcome the disadvantages ofthe prior art and in particular to overcome the problems previouslyencountered when bonding heat-activatable polyolefin adhesives topressure-sensitive adhesives. It is also desirable to provide adual-functional tape which can withstand high humidity and/or extremetemperatures without suffering from disintegration into its componentssuch that the dual-functional tape can be reliably used in bonding e.g.rubber gaskets in a vehicle, in particular a motor vehicle such as acar. A further desire is to provide an adhesive tape having improvedprocessability characteristics, particularly during heating and/orbonding the HAA layer. Desirably, the invention also provides acommercially valuable, dual-functional, adhesive tape and a method forits production. Preferably, the adhesive tape is convenient to handleand easy to apply and desirable has good flexibility.

In a first aspect, the present invention provides an adhesive tapecomprising: (A) a heat-activatable adhesive resin layer, wherein theresin is a polymer of one or more monomers selected from the groupconsisting of olefins, and (B) a pressure-sensitive adhesive layer,comprising an acrylic-type pressure-sensitive adhesive, wherein saidpressure-sensitive adhesive layer is permanently and directly bonded toa first major surface of said heat-activatable adhesive resin layer.

In a second aspect, the present invention provides a composite articlecomprising the tape according to the first aspect of the presentinvention and a rubber article bonded to the second major surface of theheat-activatable adhesive resin layer (A).

In a third aspect, the present invention provides a method of making thetape in accordance with the present invention, the method comprising thesteps of: (a) extruding a heat-activatable adhesive resin layer, (b) N₂corona treating one major surface of said heat-activatable adhesiveresin layer, (c) applying a layer of acrylic pressure-sensitive adhesiveonto the N₂ corona treated surface of said heat-activatable adhesiveresin layer. In a fourth aspect, the present invention provides anintermediate article comprising the heat-activatable adhesive resinlayer (A) releasably bonded to a support layer.

The present invention also provides a vehicle comprising the compositearticle.

The term “permanent bond” or “permanently bonded” as used in the presentinvention refers to the bond between the heat-activatable adhesive layerand the pressure sensitive adhesive layer and typically means that thebond strength between the pressure-sensitive adhesive layer and theheat-activatable adhesive layer is greater than the internal strength ofthe pressure-sensitive adhesive layer itself. Preferably, the bondstrength does not show a significant decrease over a period of time(e.g. at least a week, typically a year, preferably over several years,for example over a period of more than 10 years) and upon application offorces, such as releasing or delaminating forces.

“Significant decrease” in bond strength means a decrease in bondstrength of more than 5%, particularly of more than of 2.5% of theinitial value. In a preferred embodiment, the bond strength between thepressure sensitive adhesive layer and the heat-activatable adhesivelayer is substantially the same after one week immersion in water at 40°C. (i.e., the difference in the bond strength is less than 7%,preferably less than 5%, even more preferably less than 1 %).

In a preferred embodiment, a permanent bond in accordance with thepresent invention is such as to result in cohesive failure of thepressure-sensitive adhesive layer (i.e. spitting thereof) rather than toresult in adhesive failure of the bond between the heat-activatableadhesive layer and the pressure-sensitive adhesive layer when T-peeltesting is carried out at 300 mm/min. In other words, the bond strengthbetween the pressure-sensitive adhesive layer and the heat-activatableadhesive layer is greater than the internal strength of thepressure-sensitive adhesive layer itself.

The term “directly bonded” as used in the present invention means thatthe pressure sensitive adhesive layer is bonded to the heat-activatableadhesive resin layer without the use of any intermediate layers arrangedbetween the heat-activatable adhesive layer and the pressure-sensitiveadhesive layer, such as priming layers or intermediate layersgraft-polymerized to one of the adhesive layers.

DETAILED DESCRIPTION OF THE INVENTION

Heat-Activatable Layer (HAA)

The adhesive resin used in the heat-activatable adhesive resin layer (A)(hereinafter sometimes referred to as HAA) in accordance with thepresent invention is a polymer of one or more olefinic monomers and ishereinafter also referred to as a heat-activatable polyolefin.

The term “heat-activatable” is conventionally used in the art ofadhesive technology and means that in order to “activate” the adhesiveit needs to be subjected to a heat treatment, typically between about60° C. and about 200° C., so as to allow the heat-activatable resinlayer to bond to the desired substrate. It is preferred that the surfaceof the HAA layer be softened applying temperature near its softeningpoint, most preferably slightly above its melting point to achieve agood bond.

Examples of useful heat-activatable polyolefin resins are polyolefinhomopolymers, such as polyethylene, polypropylene, polyolefin/polyolefincopolymers, such as ethylene/propylene copolymers (often referred to aspolyallomer) and blends thereof.

Suitable blends include blends of polyethylene and polypropylene atvarious ratios. Suitable copolymers may be atactic, isotactic, random,block or impact copolymers.

Preferred heat-activatable polyolefin resins of the inventioneffectively adhere to both thermoplastic and thermoset substrates. Theadhesives achieve a high degree of compatible interfacial mixing with athermoplastic substrate while molten, which upon cooling yields ahigh-strength bond. With a thermoset substrate, the molten adhesivesachieve a superior wetting out of the substrate surface, again yieldinga high bond strength when cooled.

In one embodiment of the present invention, a propylene/ethylenecopolymer having an ethylene content of up to about 10% by weight ispreferred for use in the heat-activatable adhesive resin layer.

Polyolefin polymers which have been toughened and made impact resistantby means of incorporation of elastomeric segments into the polymericchain may also be useful. Suitable impact copolymers include impactcopolymer based on polypropylene or on polyethylene, for example impactpolypropylene copolymer containing an ethylene-propylene elastomericphase.

In another embodiment, the resin is a blend of polyethylene andpolypropylene. Preferably, the polyethylene is used in an amount of 5 to30% by weight, more preferably of 10 to 25% by weight, based on thetotal weight of the blend and the polypropylene is used in an amount of95 to 7% by weight, more preferably in an amount of 90 to 75% by weight,based on the total weight of the blend.

The heat-activatable adhesive resin in accordance with the presentinvention preferably exhibits one of the features selected from amelting point of about 120 to about 170° C. (preferably of about 130 toabout 165° C.), a melt flow index of about 2 to 18 g/10 min (preferablyof about 5 to 9 g/10 min), a tensile strength at break of about 25 toabout 45 N/cm² (preferably of about 30 to 40 N/cm²), an e-modulus at100% elongation of about 10 to about 20 N/cm² (preferably of about 12 toabout 16 N/cm), and an elongation at break of about 200 to about 450%(preferably of about 230 to about 400%). More preferably, theheat-activatable adhesive resin exhibits at least two, more preferablyat least three, and even more preferably all of the aforementionedfeatures.

Suitable commercially available heat-activatable polyolefins includepoylpropylene copolymers of the trade name FINAPRO™, such as those ofthe designation FINAPRO™ 5660, FINAPRO™ 8780, FINAPRO™ 5642, andFINAPRO™ 5712 (available from ATOFINA Petrochemicals),ethylene/propylene copolymers of the trade name ELTEX™ P, such as KS414, KS 409, or KL 467 (available from Solvay Polymers), or those of thetrade designation NOVOLEN™, such as MC 3200 (available from Targor GmbH,Ludwigshafen, Germany).

The thickness of the HAA layer is determined by the end-use of theadhesive tape typical thicknesses being in the range of about 30 to 300μm.

If desired, the heat-activatable adhesive resin layer may also containnon-resinous ingredients, such as conventional additives. Such additivesmay include fillers, pigments, dyes, crosslinking agents, viscosityadjusting agents, dispersants, extrusion aids and mixtures thereof.

Pressure-Sensitive Adhesive Layer (B)

The pressure-sensitive adhesive layer (B) in accordance with the presentinvention comprises an acrylic-type pressure-sensitive adhesive.Preferably, the pressure-sensitive adhesive layer essentially consistsof an acrylic-type pressure-sensitive adhesive.

Useful acrylic type pressure-sensitive adhesives include those known tothe person skilled in the art. Particularly useful pressure-sensitiveadhesives include ultraviolet-radiation polymerized acrylicpressure-sensitive adhesives. Preferably, these pressure-sensitiveadhesives are prepared from a composition comprising at least one alkylacrylate monomer, preferably a monofunctional unsaturated acrylate esterof a non-tertiary alcohol, the molecules of which preferably have fromabout 4 to about 14 carbon atoms. Such monomers include, e.g., isooctylacrylate, 2-ethyl hexyl acrylate, isononyl acrylate, decyl acrylate,dodecyl acrylate, butyl acrylate, and hexyl acrylate. The alkyl acrylatemonomers can be used to form homopolymers or they can be copolymerizedwith polar copolymerizable monomers. When copolymerized with stronglypolar copolymerizable monomers, the alkyl acrylate monomer generallycomprises at least about 75% of the photopolymerizable polymers. Whencopolymerized with moderately polar copolymerizable monomers, the alkylacrylate monomer generally comprises at least about 60% of thephotopolymerizable polymer.

The polar copolymerizable monomers can be selected from strongly polarcopolymerizable monomers such as acrylic acid, itaconic acid,hydroxyalkyl acrylates, cyanoalkyl acrylates, acrylamides or substitutedacrylamides, or from moderately polar copolymerizable monomers, such asN-vinyl pyrrolidone, acrylonitrile, vinyl chloride, or diallylphthalate. When strongly polar monomers are used, they preferablycomprise from about 1 to about 25 parts, preferably from about 4 toabout 20 parts of the acrylic copolymer. When moderately polar monomersare used, they preferably comprise from about 20 to about 40 parts ofthe acrylic copolymer.

The composition comprising the polymerizable monomers may also contain aphotoinitiator in order to induce polymerization of the monomers. Usefulphotoinitiators include benzoin ethers, such as benzoin methyl ether orbenzoin isopropyl ether, substituted benzoin ethers, such as anisolemethyl ether, substituted acetophenone derivatives, such as2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone,substituted alpha-ketols, such as 2-methyl-2-hydroxypropiophenone,aromatic sulfonyl chlorides, such as 2-naphthalene sulfonyl chloride,and photoactive oximes, such as 1 -phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime. Preferably, the photoinitiatoris present in an amount of about 0.01 to about 1 part per hundred parts(pph) of the acrylic monomers of the pressure sensitive adhesivecompositions.

The photopolymerizable composition may also contain a crosslinking agentto enhance heat-resistance. Preferred crosslinking agents for acrylicpressure-sensitive adhesives are multifunctional acrylates such as1,6-hexanediol diacrylates as well as those disclosed in U.S. Pat. No.4,379,201, such as trimethylolpropane triacrylate, pentaerythritoltetraacrylate, 1,2-ethylene glycol diacrylate, and 1,2-dodecanedioldiacrylate. Other useful crosslinking agents include substitutedtriazines, such as those disclosed in U.S. Pat. Nos. 4,329,384,4,391,687, 4,330,590, e.g.,2,4-bis(trichloromethyl)-6-(3,4-dimethoxyphenyl) -s-triazine and otherchromophore halogen-s-triazines. When used, the crosslinking agent ispresent in an amount of from about 0.01 to about 1 pph, wherein pphmeans (additional) parts per hundred parts of the total composition.

In one preferred embodiment, the pressure sensitive adhesive layercomprises an acrylic cellular pressure-sensitive adhesive membrane asdescribed in U.S. Pat. No. 4,415,615. A cellular pressure-sensitiveadhesive membrane is made by the steps of

-   (a) frothing a composition which is polymerizable to a    pressure-sensitive adhesive state,-   (b) coating the froth onto a backing, and-   (c) polymerizing the coated froth in situ to a pressure-sensitive    adhesive state to provide a pressure-sensitive adhesive membrane    having a cellular structure.

Frothing can be conveniently accomplished by whipping a gas into thepolymerizable composition. After coating the frothed composition onto abacking, the polymerization may be initiated by ultraviolet radiation astaught in U.S. Pat. No. 4,181,752. Where such photopolymerization isdesired, an inert frothing gas is preferably used as air tends to quenchphotopolymerization. Carbon dioxide and nitrogen are preferred frothinggases.

In another preferred embodiment, the pressure sensitive adhesive layermay be a foam-like layer. Such foam-like adhesive layers may be preparedfrom a monomer composition comprising microspheres. Suitablemicrospheres include glass or polymeric microspheres. The microspheresshould have an average diameter of 10 to 200 micrometers, and comprisefrom about 5 to about 65 volume percent of the core layer. The thicknessof foam-like layers in preferred tapes of the present invention rangesfrom 0.3 mm to about 4.0 mm in thickness.

Preferred glass microspheres have average diameters of about 50 μm. Whenglass microspheres are used, the pressure sensitive adhesive layershould be at least 3 times as thick as their diameter, preferably atleast 7 times. The thickness of layers containing such glassmicrospheres should be at least six times, preferably at least twentytimes that of each microsphere-free layer.

Polymeric microspheres are also useful for some compositions such asthose described in U.S. Pat. Nos. 3,615,972, 4,075,238, 4,287,308, and4,855,170. Such microspheres are available from Kema Nord Plastics underthe trade name “EXPANCEL” and from Matsumoto Yushi Seiyaku under thetrade name “MICROPEARL”. In expanded form, the microspheres have aspecific density of approximately 0.02–0.036 g/cc. It is possible toinclude the unexpanded microspheres in the core layer and subsequentlyheat them to cause expansion, but it is generally preferred to mix inthe expanded microspheres. This process ensures that the hollowmicrospheres in the final core layer are substantially surrounded by atleast a thin layer of adhesive.

In a highly preferred embodiment, the adhesive tape of the presentinvention may comprise a second pressure-sensitive adhesive layer. Suchsecond layer consists of a polymerized acrylic copolymer which mayincorporate similar or dissimilar acrylic monomers in like or unlikethicknesses, having similar or different additives from those acryliccopolymers contained in the first pressure-sensitive adhesive layer. Insuch an embodiment, one layer is preferably a foam-likepressure-sensitive acrylic adhesive and the second layer is anon-foam-like pressure-sensitive acrylic adhesive.

Other useful materials which may be blended into the first and/or secondpressure-sensitive adhesive layer include fillers, pigments, fibrousreinforcing agents, woven and non-woven fabrics, foaming agents,antioxidants, stabilizers, fire retardants, and viscosity adjustingagents.

An especially useful filler material is hydrophobic silica as disclosedin U.S. Pat. Nos. 4,710,536 and 4,749,590. In one preferred embodimentof the present invention, the pressure-sensitive adhesive layer furthercomprises from about 2 to about 15 pph of a hydrophobic silica having asurface area of at least 10 m²/g.

The pressure-sensitive adhesive compositions are preferably prepared bypremixing together the photopolymerizable monomers and thephotoinitiator. This premix is partially polymerized to a viscosityrange of from about 500 cps to about 5,000 cps, as measured according toASTM 4016/93, to achieve a coatable syrup. Alternatively, the monomersmay be mixed with a thixotropic agent such as fumed hydrophilic silicato achieve a coatable thickness. The crosslinking agent(s) and any otheroptional ingredients are added to the syrup prior to in situcrosslinking and polymerization.

Construction

In the adhesive tape according to the present invention the pressuresensitive adhesive layer is permanently and directly bonded to a firstmajor surface of said heat activatable adhesive resin layer. Inparticular, the adhesive tape of the present invention does not includean intermediate layer between the heat-activatable adhesive resin layerand the pressure-sensitive adhesive layer, such as layers of the typepreviously used in order to bond the pressure-sensitive adhesive to theHAA like priming layers or layers of acrylic type polymer grafted ontothe HAA.

The bond strength between the pressure-sensitive adhesive and the HAA issuch as to result in cohesive failure of the pressure-sensitive adhesivelayer rather than to result in adhesive failure of thepressure-sensitive adhesive/HAA bond in case of T-peel testing at a rateof 300 mm/min, indicating that the pressure-sensitive adhesive/HAA bondstrength is greater than the internal strength of pressure-sensitiveadhesive layer itself, even though no intermediate layer is used. Theadhesive tape of the present invention can withstand extremeenvironmental conditions such as high temperatures and/or high humidityover a long period of time.

Since no intermediate layer is needed, the tape of the present inventionis economically more valuable as compared to conventional tapes and canbe produced at reasonable costs.

The first major surface of the HAA layer may be N₂ corona treated asdescribed with respect to the method according to the present invention.In a preferred embodiment, the N₂ corona treatment is such as to resultin a surface energy as measured according to DIN 53364 of at least about40 dyne/cm, preferably at least about 45, most preferably at least about50 dyne/cm.

The adhesive tape may further include a support layer bonded to theoutermost surface, i.e. to the second major surface of theheat-activatable adhesive resin layer (A). The support layer is notparticularly restricted and a variety of materials may be employed forthe support layer. The material for the support layer is preferablyselected based on the properties of the specific HAA resin employed, andthe desired stability and handleability of the final or intermediatearticle. For example, the support layer may be comprised of polyesterpolymers, such as polyethylene terephthalate. The material of thesupport layer should be selected such that the second major surface ofthe HAA layer may be releasably bonded to the support layer. Preferably,the release force between the HAA layer and the support layer rangesfrom about 20 cN/2.54 cm to about 120 cN/2.54 cm. The support layer maybe treated in a number of known ways, in order to provide for thedesired release force value. Suitable treatments include chemicalpriming, corona treatment, or use of a tie-layer.

Preferably, a suitable support layer exhibits a thickness of about 50 toabout 100 μm, more preferably of about 60 to about 80 μm.

The present invention also relates to an intermediate article comprisingthe heat-activatable adhesive resin layer (A) according to the presentinvention releasably bonded on one major surface (the second majorsurface, i.e. that surface which will not be bonded to the acrylic typepressure-sensitive adhesive layer) to the aforementioned support layer.

Method of Manufacture

The tape of the present invention can be produced by a method comprisingthe steps of: (a) extruding a heat-activatable adhesive resin layer, (b)N₂ corona treating one major surface of said heat-activatable adhesiveresin layer, (c) applying a layer of acrylic pressure-sensitive adhesiveonto the N₂ corona treated surface of said heat-activatable adhesiveresin layer.

Extruding the heat-activatable polyolefin layer may be accomplishedaccording to methods known in the art, for example by means ofconventional extrusion equipment.

Step (a) may also include extruding the HAA onto a suitable supportlayer, thereby providing the intermediate article according to thepresent invention. If a support layer is present, the HAA will be bondedthereto by its second major surface.

The corona treatment is carried out by exposing at least the first majorsurface of heat-activatable adhesive resin layer to an electricaldischarge. The treatment can be carried out on any commercial coronatreatment equipment as will be known to those skilled in the art, forexample as described in U.S. Pat. Nos. 3,639,134, 5,639,546 or5,905,099. In accordance with the present invention, the coronatreatment is carried out in a nitrogen gas atmosphere.

The amount of energy applied can be varied dependent on net power,electrode width, speed and other parameters as will be known to theperson skilled in the art. The discharge energy density suitably rangesfrom about 15 to about 500 watts/m²/minute, preferably from about 80 toabout 250 watts/m²/minute. The energy density can be calculated from theequation:Energy Density [watts/m²/minute]=Net Power [W]/(Electrode Width [m]×Linespeed (cm/mm]).

In a preferred embodiment, the N₂ corona treatment is such as to resultin a surface energy as measured according to DIN 53364 of at least about40 dyne/cm, preferably at least about 45, most preferably at least about50 dyne/cm.

After having corona treated one major surface of the heat-activatableadhesive resin layer, a layer of acrylic pressure-sensitive adhesive isapplied onto the corona treated surface.

The time gap between the corona treatment and the application of theacrylic pressure sensitive adhesive should not be too long. The acrylicpressure-sensitive adhesive is typically applied within a period of notmore than 6 months, preferably not more than 3 months, and morepreferably within 1 month. Most preferably, the acrylic type pressuresensitive-adhesive is applied subsequently after having N₂ coronatreated the HAA layer.

In one preferred embodiment step (c) comprises laminating a preformedlayer of acrylic pressure-sensitive adhesive onto the N₂ corona treatedsurface of said heat-activatable adhesive resin layer. In thisembodiment, the HAA layer may be transparent or non-transparent, and mayinclude pigments or dyes capable of absorbing a substantial amount ofradiation.

In a particularly preferred embodiment step (c) comprises applying alayer of a radiation-curable acrylic composition onto said N₂ coronatreated surface and radiation-curing the composition in situ. In thisembodiment, the HAA layer is preferably transparent and does not absorba substantial amount of radiation during radiation-curing of thepressure-sensitive adhesive. Preferably, the HAA in this embodiment doesnot include dyes and pigments capable of absorbing a substantial amountof the radiation used for in situ curing of the adhesive composition.

A particular advantage of this preferred embodiment is that the HAAlayer may function as an in-process bottom liner, i.e. the acrylic syrupmay be directly coated onto the HAA layer without the need for anadditional transfer and laminating step of a preformed layer ofpressure-sensitive adhesive.

The acrylic-pressure-sensitive adhesive layer may finally be covered bya conventional release liner via its outermost surface.

Use

The adhesive tape of the present invention may be adhered to a widevariety of substrates by means of both, the heat-activatable adhesiveresin layer (after removal of the optional support layer, if present)and the pressure-sensitive adhesive layer (after removal of the optionalrelease liner, if present).

The adhesive tape of the present invention is particularly useful forattaching rubber articles (by means of the HAA layer) to a variety ofsurfaces (by means of the pressure-sensitive adhesive layer), as isdesired in the automotive industry. The HAA layer of the adhesive tapein accordance with the present invention provides excellent adhesion toa wide variety of rubbers and low surface energy elastomers, such asrubbers based on ethylene-propylene-diene monomer (EPDM) and/orneoprene. Specific examples include rubber brands of SANTOPRENE™(available from Monsanto Chemical Company) or rubber brands of EPDMmixed into polypropylene.

In order to bond the rubber article to the HAA layer, the optionalsupport layer on the second major surface of the HAA layer is removed.Lamination may be performed according to methods known in the art usingconventional heat-bond laminating equipment, such as aHeat-Bond-Laminator Model TE 2417 available from EHVO GmbH, Germany.Typically, a sufficient amount of heat is first applied in order toactivate the HAA layer. For instance, the HAA layer may be preheatedusing an atmosphere of air having a temperature of up to about 650° C.The preactivated tape is laminated to the desired rubber article usingan appropriate amount of pressure. The pressure-sensitive adhesive layermay serve to finally attach the resulting composite article to a varietyof surfaces, for instance to a metal surface of a car.

The present invention also relates to a vehicle comprising the compositearticle in accordance with the present invention. In a preferredembodiment, the vehicle is selected from motor vehicles, such as cars.

The present invention is illustrated by the following non-limitingexamples.

EXAMPLES

1. Test Methods

A. Characterization of Heat-activated Adhesive Resin Layer

1. Tensile Strength and Elongation at Break

Tensile strength at break (N/mm²) and elongation at break (%) of theheat-activated adhesive layer were measured according to DIN (DeutscheIndustrie Norm) Method 53455. Three dog bone-shaped samples having awidth of 6 mm and a length of 80 mm were evaluated and the resultsaveraged. The jaws of the tensile tester were separated at a rate of 508mm/min.

2. E-Modulus at 100% Elongation (N/MM²)

E-modulus of the heat-activated adhesive resin layer, measured at 100%elongation, was determined according to DIN (Deutsche Industrie Norm)Method 53455. Three dog bone-shaped samples having a width of 6 mm and alength of 80 mm were measured and the results averaged. The jaws of thetensile tester were separated at a rate of 508 mm/min.

3. Release Force Between Heat-Activated Adhesive Resin Layer and SupportLayer

The release force between the heat-activated adhesive resin layer andthe support layer was measured using a 180° Peel Adhesion Test (N/cm)according to Method PSTC4 (Pressure-Sensitive Tape Council, Chicago,Ill./USA). The peel speed of the heat-activated adhesive layer from thesupport layer was 300 mm/min.

4. Surface Energy of Heat-activated Adhesive Resin Layer After N₂-coronaTreatment

A calibrated set of commercially available felt-tip pens especiallydesigned to estimate surface energy of polyolefin films was employed tomeasure the surface tension of the heat-activated adhesive resin layerafter is had been corona treated in an atmosphere of nitrogen. The penset is available as QUICKTEST from Arcotec GmbH, Moensheim, Germany. Thesurface energy can be determined using the pen set according to DIN(Deutsche Industrie Norm) Method 53 364. The treated surface is markedwith pens containing ink having increasing surface tensions inincrements of about 2 mN/m (same numerical value as the older dyne/cmunit). In particular, a single pen QUICKTEST 38 can be used to determinewhether the surface energy of a film is above or below 38 mN/m. The bondstrength between heat-activated adhesive resin layer andpressure-sensitive adhesive layer is determined by the T-peel testdescribed below.

5. Melt Flow Index

The melt flow index can be determined according to ASTM D-1 238.

II. Sample Preparation

Samples of weatherstrip tape, about 10 mm in width and about 150 mmlong, were prepared by the procedure described in the examples.

The heat-activated adhesive side of the weatherstrip tape was thenheat-laminated to an ethylene-propylene-diene-monomer (EPDM) rubber doorseal having a Shore A hardness of 90 (obtained as EPDM Flachprofil90SHA, 3×30 mm, FP96 from Saar Gummiwerk GmbH, Wadern, Germany). Theheat lamination was performed using a commercially available equipmentobtainable as Heat-Bond Laminator MODEL TE 2417 from EHVO GmbH,Kuehnheide, Germany. This equipment preheats the EPDM rubber profiledirectly before the heat-activated adhesive surface of the weatherstriptape is pressed onto it. The temperature of the air stream used topre-heat the rubber was about 65° C. at a flow rate of 90 liters/min.The tape application speed was about 12 m/mm and the infrared radiationsetting was at 55%.

The protective liner was then removed from the pressure-sensitiveadhesive layer and replaced by an anodized aluminum strip having a widthof about 16 mm (wider than the sample) thickness of 136 μm. The aluminumstrip was pressed onto the pressure-sensitive adhesive layer byrubber-coated roller.

Bond Aging

The weatherstrip tape, heat-bonded on one side to the EPDM rubberprofile and pressure-sensitive adhesively bonded on the other side to analuminum strip, was then subjected to both of the following conditions,respectively:

-   1. Hot water immersion for 1 wk at 40° C.-   2. Temperature cycling consisting of ten (10) temperature cycles    where each cycle consisted of 16 hrs at 38° C. and 98% relative    humidity, 4 hrs at minus 40° C. and 4 hrs at 900° C.    T-Peel Test Procedure

After either one of the aging procedures above was performed, the bondedweatherstrip construction was subjected to a T-peel test. The bond linebetween the pressure-sensitive adhesive layer and heat-activatedadhesive resin layer was opened slightly by hand so that the testmeasured the strength of the bond between the heat-activated adhesivelayer and the pressure-sensitive adhesive layer. The jaws of the tensiletester grasped the end of the aluminum strip on one side and the rubberprofile on the other and pulled them apart in a T-peel mode at a rate of300 mm/min according to ASTM D-1 876-95. The data was recorded in unitsof N/6 mm of tape width and then extrapolated to give reported resultsin N/cm.

B. Release Force of the Heat-Activated Adhesive Resin Layer from theSupport Layer

A 180° Peel Adhesion test was performed at a peel speed of 300 mm/minaccording to the test method PSTC-1 (Pressure-Sensitive Tape Council,Chicago, Ill./USA). Tests were made on strip having a width of 2.54 cm.Results were reported in cN/2.54 cm.

III. Materials Employed in the Examples

FINAPRO™ PPC 5660—polypropylene impact copolymer. Melt flow index 230°C./2.16 k according to ASTM D 1238=7. Melting range 160–165° C.

Vicat softening point (10N—50° C. per hours) according to ASTM D1525=150° C. Available from Fina Chemicals, Seneffe, Belgium.

FINAPRO™ PPC 8780—a controlled-rheology heterophasic polypropylenecopolymer with a melt flow index according to ISO 1133 of 18 g/10 min.Melting point according to ISO 3146 of 165° C. Vicat softening point(50N—50° C. per hour) according to ISO 306 of 65° C. Vicat softeningpoint (10N—50° C. per hour) according to ISO 306 of 135° C. Availablefrom Fina Chemicals, Seneffe, Belgium.

FINAPRO™ PPC 5642—a nucleated impact copolymer of polypropylene. Meltflow index 230° C./2.16 kg according to ASTM D 1238=7. Melting range160–165° C. Vicat softening point (10N—50° C. per hour) according toASTM D 1525=152° C. Available from Fina Chemicals, Seneffe, Belgium.

FINAPRO™ PPC 5712—a polypropylene impact copolymer formulated with anantistatic additive package. Melt flow index 230° C./2.16 kg accordingto ASTM D 1238=7. Melting range 160–165° C. Available from FinaChemicals, Seneffe, Belgium.

ELTEX™ P KS 414—a polypropylene manufactured with SOLVAY's superactivecatalyst and continuous process. A random copolymer with a high ethylenecontent, containing slip and anti-blocking agents. Melt flow index at230° C., under 2.16 kg, according to ASTM D 1238 or ISO 1133 or DIN53735, in units of g/10 min using pellets=7.3. Melting point accordingto ASTM D 3418=134° C. Vicat Softening temperature (1 kg) according toASTM D 1525, ISO 306 or DIN 53460=120° C. Shore D hardness at 23° C.=62.Available from SOLVAY Polyolefins Europe GmbH, Brussels, Belgium.

ELTEX™ P KS 409—a polypropylene manufactured with SOLVAY's superactivecatalyst and continuous process. A random copolymer with a high ethylenecontent and no additives. Melt flow index at 230° C., under 2.16 kg,according to ASTM D 1238 or ISO 1133 or DIN 53735, in units of g/10 minusing pellets=5. Melting point according to ASTM D 3418=134° C. VicatSoftening temperature (1 kg) according to ASTM D 1525, ISO 306 or DIN53460=120° C.

Shore D hardness at 23° C.=62. Available from SOLVAY Polyolefins EuropeGmbH, Brussels, Belgium.

ELTEX™ P KL 467—polypropylene random copolymer containing slip agents.Melting point according to ISO 3146=143° C. Melt flow index (230°C./2.16 kg) in g/10 min according to ISO 1133=2.0. Available from SOLVAYPolyolefins Europe GmbH, Brussels, Belgium.

NOVOLEN™ 3200 MC—a controlled-rheology modified propylene randomcopolymer, contains no slip or antiblocking agents. Melt flow index(230° C./2.16 kg) according to ISO 1133=8. Melting temperature bydifferential scanning calorimetry (DSC) according to ISO 3146=145° C.Available from Targor GmbH, Ludwigshafen, Germany.

Example 1

Preparation of the Intermediate Article

(Heat-Activated Adhesive Resin Layer on a Support Layer)

A support layer comprising a 70 μm thick polyester (polyethyleneterephthalate) film having a 18 μm thick tie-layer extruded onto onesurface was obtained from Frantschach/AssiDomaen (Belgium).

A heat-activated adhesive resin layer of a 60 μm thick layer ofpolypropylene-ethylene random copolymer (available as FINAPRO 5660 fromFina Chemical Company) was extruded directly onto the tie-layer surfaceof the support layer using conventional extrusion equipment comprising asingle-screw extruder and a slot die.

The release force of the support layer from the heat-activatableadhesive resin layer was measured to be 20 cN/2.54 cm. This is anintermediate value which provides sufficient adhesion between the layersto permit handling of the thin heat-activated adhesive layer on thesupport without involuntary separation of the layers, but whichsimultaneously provides a low enough release force so that the supportcan be separated easily from the weatherstrip tape directly before it isheat-bonded to a rubber profile. The heat-activated adhesive layer andthe support layer were both largely transparent to UV light.

N₂ -Corona Treatment of the Heat-Activated Adhesive Resin Layer

The surface of the heat-activated layer was then subjected to coronatreatment in a nitrogen atmosphere comprising only about 10–30 ppmoxygen. A discharge energy of 5 kW was employed at a film line speed of20 m/min. The surface energy was estimated to be about 50 dyne/cm usingthe calibrated pen test method described above under TEST METHODS.

Preparation of the Syrup Precursor to the First Pressure-SensitiveAdhesive Layer

A syrup having a viscosity of about 2000 cps (Mpa.s) was prepared bysubjecting a mixture of 92.5 parts by weight isooctyl acrylate (IOA),7.5 parts by weight acrylic acid (AA) and 0.04 pph IRGACURE 651photoinitiator (available from Ciba-Geigy, Basel, Switzerland) to a UVlight source to reach a monomer conversion of about 4. Thephotopolymerization was stopped by removal of the UV light source.

All additives to the monomers were calculated in parts per hundred (pph)based on 100 parts monomer. An additional portion of 0.36 pphphotoinitiator was then added to the syrup. A crosslinker was added(hexanediol diacrylate or HDDA) in the amount of 0.12 pph based on totalmonomer. Hydrophobic fumed silica (AEROSIL 972 from Degussa) was addedto the syrup in the amount of 6 pph and mixed well. Hollow glassmicrospheres (3M SCOTCHLITE™ K 15 Glass Bubbles available from 3MCompany, St. Paul, Minn./USA) were added in the amount of 4 pph. A blackpigment, available as Pennco 9B117 UV/EB Color from PennColor Inc.,Doylestown/USA, was added at 0.35%. The resulting syrup was light gray.

Coating and Curing of the Syrup to Form a First Pressure-SensitiveAdhesive Layer

A layer of about 800 μm (0.8 mm) of the partially-polymerized acrylicsyrup described above was coated onto the N₂-corona-treated surface ofthe heat-activated adhesive resin layer using a knife-coater. The topsurface of the acrylic syrup coating was then covered with a transparentsiliconized polyester release liner.

The laminate thus prepared was exposed to UV radiation from both belowthe web (through the transparent support layer and the heat-activatedadhesive resin layer) and above the web (through the transparent liner)to effect essentially complete polymerization of the acrylic syrup. Thetotal radiation intensity was about 4.0 mW/cm² supplied from mediumpressure mercury lamps having 90% of their emission between thewavelengths of 300 nm and 400 nm with a maximum output at about 350 nm.

Preparation of a Second Layer of Acrylic Pressure-Sensitive Adhesive

A primer layer comprising a polyamide (available as MACROMELT™ 6240 fromHenkel GmbH, Duesseldorf, Germany) was then prepared by coating asolution of 10 parts by weight polyamide, 50 parts by weight isopropanoland 50 parts by weight n-propanol onto a release liner and drying in aforced air oven.

An acrylic pressure-sensitive adhesive (PSA) comprising 65 partsisooctyl acrylate (IOA), 5 parts acrylic acid (AA) and 30 parts methylacrylate (MA) was prepared by solution polymerization according to themethod described in U.S. Patent Reissue 24,906 (Ulrich). A 50 μm thicklayer of the acrylic adhesive was then placed on top of the polyamideprimer layer by coating the solution polymer onto the polyamide layerand drying.

Lamination of Second Pressure-Sensitive Adhesive Layer to the FirstPressure-Sensitive Adhesive Layer

The top temporary polyester liner present during the radiationpolymerization was then removed from the first layer of acrylicpressure-sensitive adhesive.

The second thinner acrylic adhesive layer bearing the polyamide primerwas laminated on top of the first thicker acrylic adhesive layer in afashion so that the primer layer was located between the two layers ofacrylic pressure-sensitive adhesive.

The paper liner covering the second layer of acrylic adhesive was thenremoved, and a more heat-resistant polymeric film-based release linerwas put in its place.

The bottom support layer adjacent to the heat-activated adhesive layerwas then stripped away leaving the heat-activatable adhesive layerexposed and ready for bonding to a flexible rubber profile designed toseal vehicle doors.

Testing

The laminate thus prepared was tested according to the method givenabove under TEST METHODS.

Test results of the T-peel measurements after 24 hours at 23° C. showedthat the bond strength between the acrylic foam and the heat-activatedfilm was go great that the foam itself split cohesively during theT-peel test. No separation of the bond between the heat-activated filmand the acrylic foam could be observed.

Additional test results are summarized in Table 2.

Examples 2–10

Example 1 was repeated with the sole exception that each of thepolyolefin layers given were employed in place of FINAPRO 5660. Eachpolymer indicated was, in turn, extruded onto the polyester supportlayer as described in Example 1 and employed as the heat-activatablefilm layer in the weatherstrip construction.

Chemical composition and properties of the polyolefin polymers employedare summarized in Table 1.

The test results on the completed weatherstrip constructions are givenin Table 2.

TABLE 1 Physical properties of heat-activated adhesive films Melt flowe-mod at Tens. at Elong. at M. P. index (2) 100% elong. break (4) break(4) Ex. Tradename (1) ° C. g/10 min (3) N/cm² N/cm² % 1 FINAPRO ™ 5660160 7 15 35 379 2 FINAPRO ™ 8780 160 18 13 27 232 3 FINAPRO ™ 5642 160 71.5 34 380 4 FINAPRO ™ 5712 160 7 14 32 390 5 ELTEX ™ P KS 414 134 7.312 34 394 6 ELTEX ™ P KS 409 134 5 1.1 30 396 7 ELTEX ™ KL 467 143 2 1341 400 8 Novolen ™ MC 3200 145 11 14 39 402 9 BIend PP/PE 90/10 — —11.53 26.3 357 10 Blend PP/PE 75/25 — — 11.46 28.0 381 (1) ASTM D-3418,values taken from manufacture's literature (2) ASTM D-1238, values takenfrom manufacture's literature (3) DIN 53457, measured independently (4)DIN 53 455, measured independently

Example 11

Example 1 was repeated with the exception that both the thicker acrylicfoam pressure-sensitive adhesive layer and the thinner acrylicpressure-sensitive adhesive transfer tape were prepared separately andthen transferred onto the nitrogen corona-treated, heat-activatedadhesive layer.

T-peel measurements after hot water aging and temperature cycling areshown in Table 2 and demonstrate that the adhesive bond as formed bytransferring a preformed pressure-sensitive adhesive tape as ifpolymerizing the acrylic type adhesive in situ.

Comparative Example 1

Example 1 was repeated with the exception that the surface of theheat-activated film was prepared for bonding by coating it with a thinfilm of acrylic monomers and then radiation grafting them onto thesurface as described in EP-A-0 384 598 (3M). The acrylicpressure-sensitive adhesive layer was then transferred onto thechemically grafted surface of the heat-activated adhesive layer.

T-peel measurements after aging of laminates in hot water and aftertemperature cycling are summarized in Table 2 and show adhesive failurebetween the heat-activated adhesive layer and the pressure-sensitiveadhesive layer.

TABLE 2 Test results Method of application of T-peel after Treatment forpressure-sensitive adhesive water imm. 1 T-peel after 10 heat-activatedlayer to heat-activated wk 40° C., temp. Cycles, Ex. adhesive layeradhesive layer N/cm N/cm  1 N₂ corona On-web polym. 30 coh** Failure inthe treatment EPDM rubber  2 N₂ corona Polym. Of PSA directly on 32coh** Failure in the treatment heat-activated adhesive EPDM rubber  3 N₂corona Polym. Of PSA directly on treatment heat-activated adhesive  4 N₂corona Polym. Of PSA directly on treatment heat-activated adhesive  5 N₂corona Polym. Of PSA directly on treatment heat-activated adhesive  6 N₂corona Polym. Of PSA directly on treatment heat-activated adhesive  7 N₂corona Polym. Of PSA directly on treatment heat-activated adhesive  8 N₂corona Polym. Of PSA directly on 25 coh** 25* treatment heat-activatedadhesive  9 N₂ corona Polym. Of PSA directly on treatment heat-activatedadhesive 10 N₂ corona Polym. Of PSA directly on treatment heat-activatedadhesive 11 N₂ Corona Transfer of finished 28 coh**  28** treatmentpressure-sensitive adhesive layer C1 In-situ graft Transfer of finished8 adh* 30* polymerization pressure-sensitive adhesive of a primer layerlayer. Adh* = adhesive failure between pressure-sensitive adhesive layerand heat-activated adhesive layer Coh** = cohesive (internal) failure ofthe pressure-sensitive adhesive layer, indicating the strength of thebond between the pressure-sensitive adhesive layer and theheat-activated adhesive resin layer is higher than the internal strengthof the pressure-sensitive adhesive layer itself.

1. An adhesive tape comprising: (A) a heat-activatable adhesive resinlayer, wherein the resin is a polymer of one or more olefinic monomers,and (B) a pressure-sensitive adhesive layer, comprising an acrylic-typepressure sensitive adhesive, wherein said pressure sensitive adhesivelayer is permanently and directly bonded to a first major surface ofsaid heat-activatable adhesive layer and said first major surface hasbeen N₂ corona treated.
 2. The tape of claim 1, wherein said permanentbond between said pressure-sensitive adhesive layer and saidheat-activatable layer is such as to result in cohesive failure of thepressure sensitive adhesive layer in case of T-peel testing at a rate of300 mm/mm.
 3. The tape of claim 1, wherein said heat-activatableadhesive resin exhibits at least one of the features selected from amelting point of about 120 to about 170° C., a melt flow index of about2 to 18 g/10 mm, a tensile strength at break of about 25 to 45 N/cm , ane-modulus at 100% elongation of about 10 to about 20 N/cm², and anelongation at break of about 200 to 450%.
 4. The tape of claim 1,wherein said heat-activatable adhesive resin is selected frompolypropylene, polyethylene, ethylene/propylene copolymers, and mixturesthereof.
 5. The tape of claim 1, wherein said heat-activatable adhesiveresin is an impact polypropylene copolymer containing anethylene-propylene elastomeric phase.
 6. The tape of claim 1, whereinsaid layer (A) has a thickness of 30 to 300 μm.
 7. The tape of claim 1,wherein said acrylic-type pressure-sensitive adhesive is a homopolymeror copolymer derived from a radiation curable acrylic compositioncomprising at least one C₄–C₁₄ alkyl acrylate monomer.
 8. The tape ofclaim 7, wherein said acrylic-type pressure-sensitive adhesive furthercomprises microspheres selected from glass microspheres and polymericmicrospheres and mixtures thereof.
 9. The tape of claim 1, wherein saidacrylic-type pressure-sensitive adhesive comprises (a) at least about 60parts of an alkyl acrylate monomer, the alkyl groups of which have anaverage of 4 to 12 carbon atoms, and (b) correspondingly, up to about 40parts of a monoethylenically unsaturated polar copolymerizable monomer,and (c) from about 0.01 part to about 10 parts of a photoinitiator per100 parts of monomer.
 10. The tape of claim 9, wherein said acrylic-typepressure-sensitive adhesive comprises from about 60 to about 99 parts ofan alkyl acrylate monomer selected from isooctyl acrylate, butylacrylate, isononyl acrylate, 2-ethyl-hexyl acrylate, and isodecylacrylate, and correspondingly, from about 1 part to about 40 parts of apolar copolymerizable monomer, said polar copolymerizable monomer beingselected from acrylic acid, itaconic acid, n-vinyl pyrrolidone, N-vinylcaprolactam, acrylamide, substituted acrylamide, and methacrylic acid.11. The tape of claim 1, wherein said acrylic-type pressure-sensitiveadhesive is a cellular pressure-sensitive adhesive.
 12. The tape ofclaim 1, further comprising a second layer of acrylic-type pressuresensitive adhesive.
 13. The tape of claim 1, further comprising asupport layer releasably bonded to a second major surface of saidheat-activatable adhesive layer (A).
 14. A composite article comprisingthe tape of claim 1 and a rubber article bonded to a second majorsurface of the heat-activatable layer (A).
 15. A method of making anadhesive tape, comprising the steps of: (a) extruding a heat-activatableadhesive resin layer, wherein the resin is a polymer of one or moreolefinic monomers, (b) N₂ corona treating a first major surface of saidheat-activatable adhesive resin layer, and (c) applying a layer of anacrylic-type pressure-sensitive adhesive onto the N₂ corona treatedsurface of said heat-activatable adhesive resin layer, wherein saidpressure sensitive adhesive layer is permanently and directly bonded tothe first major surface of said heat-activatable adhesive layer.
 16. Themethod of claim 15, wherein step (c) comprises applying a layer of aradiation-curable acrylic composition onto said N₂ corona treatedsurface and radiation-curing the composition in situ.
 17. The method ofclaim 15, wherein step (c) comprises laminating a preformed layer ofacrylic pressure-sensitive adhesive onto the N₂ corona treated surface.18. An intermediate article comprising the heat-activatable adhesiveresin layer (A) as described in claim 1 releasably bonded to a supportlayer.
 19. A vehicle comprising the composite article of claim
 14. 20. Avehicle according to claim 19 wherein said vehicle is a motor vehicle.21. The tape of claim 1, wherein a weatherstrip is bonded to a secondmajor surface of said heat-activatable adhesive layer.
 22. The tape ofclaim 21, wherein said weatherstrip is manufactured from at least one ofethylene-propylene-diene monomer and neoprene.
 23. The tape of claim 21,wherein said weatherstrip is manufactured from a low surface energyelastomer.
 24. The tape of claim 1, wherein an automotive weatherstripis bonded to a second major surface of said heat-activatable adhesivelayer.
 25. The tape of claim 24, wherein said automotive weatherstrip ismanufactured from at least one of ethylene-propylene-diene monomer andneoprene.
 26. The tape of claim 24, wherein said automotive weatherstripis manufactured from a low surface energy elastomer.
 27. The tape ofclaim 1, wherein said pressure-sensitive adhesive layer and saidheat-activatable layer are permanently bonded together such that thebond between said pressure-sensitive adhesive layer and saidheat-activatable layer is greater than the internal strength of saidpressure sensitive adhesive layer itself.